/*
 * Copyright (c) 2016 Cisco and/or its affiliates.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package io.fd.hc2vpp.v3po.write;

import io.fd.hc2vpp.common.translate.util.AbstractInterfaceTypeCustomizer;
import io.fd.hc2vpp.common.translate.util.AddressTranslator;
import io.fd.hc2vpp.common.translate.util.JvppReplyConsumer;
import io.fd.hc2vpp.common.translate.util.NamingContext;
import io.fd.hc2vpp.v3po.DisabledInterfacesManager;
import io.fd.honeycomb.translate.write.WriteContext;
import io.fd.honeycomb.translate.write.WriteFailedException;
import io.fd.jvpp.core.dto.VxlanAddDelTunnel;
import io.fd.jvpp.core.dto.VxlanAddDelTunnelReply;
import io.fd.jvpp.core.future.FutureJVppCore;
import java.util.concurrent.CompletionStage;
import javax.annotation.Nonnull;
import org.opendaylight.yang.gen.v1.http.fd.io.hc2vpp.yang.v3po.rev190527.L2Input;
import org.opendaylight.yang.gen.v1.http.fd.io.hc2vpp.yang.v3po.rev190527.NshProxy;
import org.opendaylight.yang.gen.v1.http.fd.io.hc2vpp.yang.v3po.rev190527.VxlanTunnel;
import org.opendaylight.yang.gen.v1.http.fd.io.hc2vpp.yang.v3po.rev190527.interfaces._interface.Vxlan;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev130715.IpAddressNoZone;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.interfaces.rev180220.InterfaceType;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.interfaces.rev180220.interfaces.Interface;
import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class VxlanCustomizer extends AbstractInterfaceTypeCustomizer<Vxlan> implements JvppReplyConsumer {

    private static final Logger LOG = LoggerFactory.getLogger(VxlanCustomizer.class);

    private final NamingContext interfaceNamingContext;
    private final DisabledInterfacesManager interfaceDisableContext;

    public VxlanCustomizer(@Nonnull final FutureJVppCore vppApi,
                           @Nonnull final NamingContext interfaceNamingContext,
                           @Nonnull final DisabledInterfacesManager interfaceDisableContext) {
        super(vppApi);
        this.interfaceNamingContext = interfaceNamingContext;
        this.interfaceDisableContext = interfaceDisableContext;
    }

    @Override
    protected Class<? extends InterfaceType> getExpectedInterfaceType() {
        return VxlanTunnel.class;
    }

    @Override
    protected final void writeInterface(@Nonnull final InstanceIdentifier<Vxlan> id, @Nonnull final Vxlan dataAfter,
                                        @Nonnull final WriteContext writeContext)
            throws WriteFailedException {
        final String swIfName = id.firstKeyOf(Interface.class).getName();
        createVxlanTunnel(id, swIfName, dataAfter, writeContext);
    }

    @Override
    public void deleteCurrentAttributes(@Nonnull final InstanceIdentifier<Vxlan> id, @Nonnull final Vxlan dataBefore,
                                        @Nonnull final WriteContext writeContext)
            throws WriteFailedException {
        final String swIfName = id.firstKeyOf(Interface.class).getName();
        deleteVxlanTunnel(id, swIfName, dataBefore, writeContext);
    }

    private void createVxlanTunnel(final InstanceIdentifier<Vxlan> id, final String swIfName, final Vxlan vxlan,
                                   final WriteContext writeContext)
            throws WriteFailedException {
        final byte isIpv6 = (byte) (isIpv6(vxlan)
                ? 1
                : 0);

        int encapVrfId = vxlan.getEncapVrfId().getValue().intValue();
        int vni = vxlan.getVni().getValue().intValue();

        int decapNext = -1;
        if (vxlan.getDecapNext() == L2Input.class) {
            decapNext = 1;
        } else if (vxlan.getDecapNext() == NshProxy.class) {
            decapNext = 2;
        }

        LOG.debug("Setting vxlan tunnel for interface: {}. Vxlan: {}", swIfName, vxlan);
        final CompletionStage<VxlanAddDelTunnelReply> vxlanAddDelTunnelReplyCompletionStage =
                getFutureJVpp().vxlanAddDelTunnel(getVxlanTunnelRequest((byte) 1 /* is add */, vxlan.getSrc(),
                        vxlan.getDst(), encapVrfId, decapNext, vni, isIpv6));

        final VxlanAddDelTunnelReply reply =
                getReplyForCreate(vxlanAddDelTunnelReplyCompletionStage.toCompletableFuture(), id, vxlan);
        LOG.debug("Vxlan tunnel set successfully for: {}, vxlan: {}", swIfName, vxlan);
        if (interfaceNamingContext.containsName(reply.swIfIndex, writeContext.getMappingContext())) {
            // VPP keeps vxlan tunnels present even after they are delete(reserving ID for next tunnel)
            // This may cause inconsistencies in mapping context when configuring tunnels like this:
            // 1. Add tunnel 2. Delete tunnel 3. Read interfaces (reserved mapping e.g. vxlan_tunnel0 -> 6
            // will get into mapping context) 4. Add tunnel (this will add another mapping with the same
            // reserved ID and context is invalid)
            // That's why a check has to be performed here removing mapping vxlan_tunnel0 -> 6 mapping and storing
            // new name for that ID
            final String formerName = interfaceNamingContext.getName(reply.swIfIndex, writeContext.getMappingContext());
            LOG.debug("Removing updated mapping of a vxlan tunnel, id: {}, former name: {}, new name: {}",
                    reply.swIfIndex, formerName, swIfName);
            interfaceNamingContext.removeName(formerName, writeContext.getMappingContext());

        }

        // Removing disability of an interface in case a vxlan tunnel formerly deleted is being reused in VPP
        // further details in above comment
        if (interfaceDisableContext.isInterfaceDisabled(reply.swIfIndex, writeContext.getMappingContext())) {
            LOG.debug("Removing disability of vxlan tunnel, id: {}, name: {}", reply.swIfIndex, swIfName);
            interfaceDisableContext.removeDisabledInterface(reply.swIfIndex, writeContext.getMappingContext());
        }

        // Add new interface to our interface context
        interfaceNamingContext.addName(reply.swIfIndex, swIfName, writeContext.getMappingContext());
    }

    private boolean isIpv6(final Vxlan vxlan) {
        return vxlan.getSrc().getIpv4AddressNoZone() == null;

    }

    private void deleteVxlanTunnel(final InstanceIdentifier<Vxlan> id, final String swIfName, final Vxlan vxlan,
                                   final WriteContext writeContext) throws WriteFailedException {
        final byte isIpv6 = (byte) (isIpv6(vxlan)
                ? 1
                : 0);

        int encapVrfId = vxlan.getEncapVrfId().getValue().intValue();
        int vni = vxlan.getVni().getValue().intValue();

        int decapNext = -1;
        if (vxlan.getDecapNext() == L2Input.class) {
            decapNext = 1;
        } else if (vxlan.getDecapNext() == NshProxy.class) {
            decapNext = 2;
        }

        LOG.debug("Deleting vxlan tunnel for interface: {}. Vxlan: {}", swIfName, vxlan);
        final CompletionStage<VxlanAddDelTunnelReply> vxlanAddDelTunnelReplyCompletionStage =
                getFutureJVpp().vxlanAddDelTunnel(getVxlanTunnelRequest((byte) 0 /* is add */, vxlan.getSrc(),
                        vxlan.getDst(), encapVrfId, decapNext, vni, isIpv6));

        getReplyForDelete(vxlanAddDelTunnelReplyCompletionStage.toCompletableFuture(), id);
        LOG.debug("Vxlan tunnel deleted successfully for: {}, vxlan: {}", swIfName, vxlan);

        final int index = interfaceNamingContext.getIndex(swIfName, writeContext.getMappingContext());
        // Mark this interface as disabled to not include it in operational reads
        // because VPP will keep the interface there
        LOG.debug("Marking vxlan tunnel as disabled, id: {}, name: {}", index, swIfName);
        interfaceDisableContext.disableInterface(index, writeContext.getMappingContext());
        // Remove interface from our interface naming context
        interfaceNamingContext.removeName(swIfName, writeContext.getMappingContext());
    }

    private static VxlanAddDelTunnel getVxlanTunnelRequest(final byte isAdd, final IpAddressNoZone srcAddr,
                                                           final IpAddressNoZone dstAddr,
                                                           final int encapVrfId,
                                                           final int decapNextIndex, final int vni, final byte isIpv6) {
        final VxlanAddDelTunnel vxlanAddDelTunnel = new VxlanAddDelTunnel();
        vxlanAddDelTunnel.isAdd = isAdd;
        vxlanAddDelTunnel.srcAddress = AddressTranslator.INSTANCE.ipAddressToArray(srcAddr);
        vxlanAddDelTunnel.dstAddress = AddressTranslator.INSTANCE.ipAddressToArray(dstAddr);
        vxlanAddDelTunnel.encapVrfId = encapVrfId;
        vxlanAddDelTunnel.vni = vni;
        vxlanAddDelTunnel.decapNextIndex = decapNextIndex;
        vxlanAddDelTunnel.isIpv6 = isIpv6;
        return vxlanAddDelTunnel;
    }
}
